Recently, with a vigorous development in a semiconductor technology, portable electronics and panel display products rise up accordingly. A Thin Film Transistor (TFT) liquid crystal display has become a standard output device for the various electronics gradually, because it has advantages such as a low operation voltage, no scattering from radiant rays, a light weight, a small volume, etc. As system integrities of various display devices, such as mobile phones, tablet PCs (PAD), are higher and higher and their thicknesses are thinner and thinner, a Central Processing Unit (CPU) of the system has been upgraded to a dual-core product system, a quad-core product system, an octa-core product system or even a product system with more cores from a previous single-core product system. However, a power consumption of the system is higher and higher, and requirements for an endurance time of the mobile phone and the PAD are also higher and higher, such that a continuing decreasing of the power consumption of the display device is a target pursued continually by system manufacturers and panel manufacturers.
The TFT liquid crystal display generally comprises a pixel matrix arranged in the horizontal direction and vertical direction, and when the TFT liquid crystal display displays an picture, gate input signals, namely signals G1, G2, . . . , Gn outputted from a driving circuit, are generated by the shift registers (SRs), and then the pixels in respective rows are scanned from the first row to the last row sequentially, as illustrated in FIG. 1. A gate driving clock signal CPV is input to an input terminal of each shift register, and a gate scanning trigger signal STV is input to the input terminal of the first stage of shift register unit SR1. In the design for the existing TFT liquid crystal device, the TFT liquid crystal display would perform a black-scan action when it is in a partial display state, that is to say, the gates of the TFT liquid crystal display would scan row by row from top to bottom, while source driving signals (that is, on data lines) remain at a low level all the time so as not to charge the TFT liquid crystal display, so that the power consumption of a source driving chip is reduced; the corresponding logic timing of the gates is as illustrated in FIG. 2.
The existing circuit design only reduces the power consumption of the source driving circuit, however, when the TFT liquid crystal display is in the partial display state, for example, when a movie with an aspect ratio of 16:9 is played back in a full screen mode on a screen with the aspect ratio of 4:3, black margins (that is, a black-scan area) exist at the top and bottom of the screen, while the gate driving circuit still scans row by row from top to bottom without shutting off the gate signals for the black-scan area, such that the power consumption of the gate driving circuit is not reduced and a whole power consumption of the liquid crystal display is still great.